How do we know we can trust the historical surface temperature record? Did global warming stop in 1998? What actions can businesses or individuals take to reduce climate chagne from greenhouse gas emissions? Get asnwers to these and other frequently asked questions.

From reindeer to regional temperature patterns, from sea ice age to Greenland surface melt, the Arctic Report Card is a yearly assessment of the Arctic's physical and biological systems and how they are changing. This collection of visual highlights from the 2013 report is a story of the Arctic in pictures.

Since the mid-1960s, the Arctic has warmed about 3.6°F (2.0°C)—more than double the amount of warming in lower latitudes. In 2012 (the last complete calendar year available at the time scientists began working on the 2013 Arctic Report Card), the annual average temperature was the sixth warmest on record.

In May 2013, there was record-setting loss of Eurasian spring snow cover, and spring snow cover was below normal again in June—the fourth lowest on record. This is the sixth year in a row that Eurasia has set a new record low in either May or June snow extent.

Averaged over September 2013, sea ice extent was 2.07 million square miles—larger than last year's record low, but still more than 17 percent below average and the sixth smallest September extent on record.